(VAR M N X1 X2 X3 X) (RULES a__U11(tt,M,N) -> a__U12(tt,M,N) a__U12(tt,M,N) -> s(a__plus(mark(N),mark(M))) a__U21(tt,M,N) -> a__U22(tt,M,N) a__U22(tt,M,N) -> a__plus(a__x(mark(N),mark(M)),mark(N)) a__plus(N,0) -> mark(N) a__plus(N,s(M)) -> a__U11(tt,M,N) a__x(N,0) -> 0 a__x(N,s(M)) -> a__U21(tt,M,N) mark(U11(X1,X2,X3)) -> a__U11(mark(X1),X2,X3) mark(U12(X1,X2,X3)) -> a__U12(mark(X1),X2,X3) mark(plus(X1,X2)) -> a__plus(mark(X1),mark(X2)) mark(U21(X1,X2,X3)) -> a__U21(mark(X1),X2,X3) mark(U22(X1,X2,X3)) -> a__U22(mark(X1),X2,X3) mark(x(X1,X2)) -> a__x(mark(X1),mark(X2)) mark(tt) -> tt mark(s(X)) -> s(mark(X)) mark(0) -> 0 a__U11(X1,X2,X3) -> U11(X1,X2,X3) a__U12(X1,X2,X3) -> U12(X1,X2,X3) a__plus(X1,X2) -> plus(X1,X2) a__U21(X1,X2,X3) -> U21(X1,X2,X3) a__U22(X1,X2,X3) -> U22(X1,X2,X3) a__x(X1,X2) -> x(X1,X2) )